Abstract

The anaerobic degradability of wool scouring effluent was investigated in batch cultures. The results were compared to the degradation of cellulose and sterile activated sludge. Wool scouring effluent was clearly more difficult to degrade anaerobically than cellulose or the biomass of activated sludge. The maximum biogas production rate from wool scouring effluent was about 46% and 31 % of the maximal rates obtained from activated sludge and cellulose powder, respectively. The slow conversion rate and also the low percentage of the organics degraded showed that wool scouring effluent is particularly difficult to degrade anaerobically. Our results suggest that very long residence times (> 30 days) are required to successfully convert most of the organics in wool scouring effluent into biogas. The large digester size required questions the economics of such a treatment. However, in contrast to waste streams containing communal wastes, biomass waste or carbohydrates, wool scouring effluent as feed material is unlikely to cause digester failure by acidification, which would make its anaerobic digestion more stable and more easily controlable.